Monaz: Hello, I'm Monaz Mehta, editor in the Cochrane Editorial and Methods department. Rotavirus infection is a common cause of diarrhea and a variety of vaccines are used to try to prevent it. The evidence for these is examined in the fourth update of a Cochrane Review, published in March 2019 and we asked Hanna Bergman one of the authors based in the Cochrane Response team in London UK to tell us about the problem and the latest findings.

Hanna: Rotavirus infection is common across the world and although some babies and young children might not develop any symptoms, others might get so ill that they need to go into hospital and some may die. Most of the deaths associated with rotavirus occur in children in low- and middle-income countries, particularly sub-Saharan Africa and the Indian subcontinent. Before children started being vaccinated, rotavirus infection caused almost half a million deaths per year in children under five. 
Since 2009, the World Health Organization has recommended that a rotavirus vaccine be included in all national infant and child immunization programmes, and almost 100 countries currently do so. Therefore, we have updated this review in order to examine the latest evidence on both the benefits and the potential side effects of the rotavirus vaccines that have been prequalified by the WHO for preventing diarrhea and deaths in infants and young children. We also looked at whether the effects differ when the vaccines are used in countries with high or low mortality rates.
We included 55 randomized trials in more than 200,000 infants and young children that had compared one of the vaccines against a placebo or no vaccine. Two of the three vaccines tested, Rotarix and RotaTeq, have been studied in several large global clinical trials and are approved for use in many countries, On the other hand, the third vaccine, Rotavac has only been evaluated in India and is only in use there.
Pooling the trial results suggests that the total number of cases of severe rotavirus diarrhea were reduced by between 35 and 63% after vaccination in high mortality countries and by 82 to 92% after vaccination in low mortality countries, in the couple of years after vaccination. We also found a small reduction in diarrhea from any cause and a large reduction in rotavirus-related hospitalizations and healthcare encounters as a result of vaccination. We did not detect a reduction in mortality, but unlike the other outcomes I’ve mentioned, the evidence for this was of low to very low certainty because there were so few deaths in the trials.
Turning to the side effects, we didn’t find any increased risk of serious adverse events as a result of using the vaccines but we could not exclude the possibility of a small risk of rare serious adverse events. Like with previous rotavirus vaccines, monitoring for these events is ongoing in countries that have introduced rotavirus vaccine and we may have more to say about this in future updates of this review.
To finish and as the take home message, our review shows that Rotarix, RotaTeq and Rotavac do prevent rotavirus diarrhoea and have comparable safety and efficacy profiles.

Monaz: Thanks Hanna. If you would like to read more about these vaccines, and watch for the fifth update of this review if additional evidence becomes available, simply go online to cochrane library dot com and search ‘rotavirus vaccines’ for free access to the full review.